多频情况下存在绝缘故障的叠片铁心的涡流及涡流损耗的分析

Analysis of Eddy Current and Associated Losses Insulated Faults Involved in Laminated Iron Core Under Various Frequencies

提出了一种分析叠片铁心发生绝缘故障时故障区域内的涡流及涡流损耗的方法。该方法以利用矢量电位和标量磁位,T,ψ-ψ方程的有限元方法为基础,使用最新发展的均质化方法模拟发生绝缘故障时的叠片铁心。为计算不同频率下的场量,推导出了各向异性铁心中不同方向的有效趋肤深度,且利用自适应网格完成趋肤深度的剖分。为证明方法的有效性,本文分别计算了不同频率下发生绝缘故障的大型异步电动机铁心中的涡流及涡流损耗。并将获得结果与采用直接方法获得的结果进行对比分析。结果表明,低频情况下利用各向异性电导率的连续体模型获得的结果可以很好地满足实际的精度需要。

This paper presents a method for analyzing the eddy current fields and resultant losses in the insulation fault zone of laminated iron core which occur the insulated faults. It is based on the finite-element method which uses the three-dimensional magnetic scalar potential magneto dynamic T, ψ-ψ formulation and a newly developed homogenization method is applied to model the laminations with the insulated faults effectively. In order to compute fields at various frequencies, the formulas for the effective skin depths along different directions in the anisotropic solid core are derived, which are accompanied with the adaptively generated finite-element meshes. As an example of application of the method developed above, the eddy current and associated losses in a large asynchronous machine core with insulated faults are computed over a very wide frequency range. The calculations results, based on the homogenization model by introducing anisotropic conductivity and on the direct method involving the actual description of lamination, respectively, are analytical comparison. The results of the comparison display the stator faults analyzed by the continuum model with the anisotropic conductivity can satisfy the actual accuracy requirement at low frequencies.